Improvement in adding-machines



D. CARROLL.

ADDING-MACHINE.

Patenta& May &1875.

ATTOBNEYS.

WASHINGTDN D C WITNESSES UNITED STATES PATENT OFFICE,

DAVID OARROLL, OF SPRING GREEK, PENNSYLVANIA.

IMPROVEMENT IN ADDlNG-MACHINES.

Specitication forming part of Letters Patent No. !76,833, eted May 2, 1876; application filed February 28, 1876.

one by the thumb, and also rranged so that euch one turns the unit-wheel the number of figures that it stands for.

Figure l is a sectional elevation of my improved machine taken on line w a? of Fig. 2. Fig. 2 is it sectional elevation taken on line y y of Fig. 1. Fig. 3 is a sectional elevation taken on line z z ot' Fig. 2; ztnd'Fig. 4is a top view.

Similar letters ofreference indicate corresponding parts.

A represents the keys, which are arranged in two rows -ucross the top of the case B, to pass down the trendle U for working the wheel D by the pawl E, which is so genred with the wheel as to turn it half the movement when pressed down by a key, and the other halt' when raised up by the spring F. The full stroke of the treadle turns the wheel ten teeth, or once around, and shorter strokes in proportion to their length. The keys are constructed as to length, and connect by adjusting-screws Gr, so that when the knobs H are pushed down to the top of the case they turn the wheel the number of teeth eorresponding to the number of the key.

To prevent the wheel D from turning too far, there ere stop-pawls I, which engage ratchetwheel J at the moment the pawl E stops in the downwa rd movement, said pawls being worked bythe treadles K L, one of which is worked by one row of keys, and one by the other.

' To turn the higher wheels by the lower ones, a, piu, N, ou the lower wheel pushes pin O of pawl P out of the notch of the higher wheel by acting on stud Q ot' the pztwl, and, when pin N passes, the stud spring -R pulls the pnwl back, and the pawl sets the wheel around one number by the pusher S. The sliding rol T and the pivoted blocks U disconnect the puwls P-when the wheels are to be set back to zero, which is done by turniug them by the thunb-kuob V, the ratchet E atllowing wheel D to turn back readily.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. The combinution of the double ratchetbar E, spring F, treadle G, and screws Gr with the double series of keys A and the numberwheel D, having :t spur-wheel on its sha't, as and for the purpose set forth.

2. The combinzttion of the independent treadles K L and the stop-pawls I, with the double series of keys and the rutchet of the numberwheel D, us and for the purpose set forth.

3. The sliding rod T and the pivoted bloeks U, in combination with the pawls P, substantially as specified.

DAVID GARROLL.

Witnesses:

E. R. WILKINs, S. D. GREEN. 

